Saturday, April 30, 2016

This summer, the Aedes aegypti mosquito will begin its proliferation throughout much of the

southern and eastern United States,
and fears about the Zika virus, which the insects can carry and
transmit, will no doubt reach a fever pitch. But a major outbreak of
Zika is unlikely in the continental U.S. (though “local outbreaks”
affecting a few dozen people are projected to occur),
just as the country doesn’t see widespread outbreaks of dengue, also
carried by Aedes aegypti, outside of a few individual cases. That’s due,
in part, to a sturdy and aggressive program of mosquito control in the
country. But as all eyes turn to mosquito prevention, new
research released Saturday finds a connection between one common method
of mosquito control—spraying insecticide from planes—and heightened
incidence of autism in children born where it occurs.

Outside of a posting on a government website, or perhaps notifications by mail, you might not know it, but in many places in the U.S. (including nearly every ZIP code
in New York City) larvicides are sprayed from planes on neighborhoods
to combat mosquitoes. When Steve Hicks, a physician and assistant
professor of pediatrics at Penn State College of Medicine, looked at
rates of autism diagnoses in eight ZIP codes where aerial spraying of
pyrethroids, a common class of insecticides, happens in the summer
months, and compared them with those in 16 surrounding ZIP codes where
mosquito control is done primarily through pellets distributed on the
ground, he and his team found a 25 percent higher rate of autism among
the plane-sprayed group.

Of the 19,000 kids living in the eight ZIP codes sprayed by planes,
there were 159 cases of autism (0.84 percent). In the 16 control ZIP
codes, 298 out of 44,000 children (0.67 percent) were diagnosed with
autism. Overall, both rates are lower than the national average for
autism, but Hicks says that could be due to the fact that his team
relied on data from children who came through SUNY Upstate University
Hospital, a regional medical center, potentially leaving out children
who were diagnosed by their family doctors and never went to the
regional center.

The research stemmed from an earlier major study known as the CHARGE Study
(Childhood Autism Risks From Genetics and the Environment), which found
that if pregnant mothers in their third trimester were exposed to
pyrethroids and two other common pesticides their children were much more likely to be diagnosed with autism.

The ZIP codes in the latest study are all northeast of the city of Syracuse, New York, near an area called Cicero Swamp,
where, as the name suggests, mosquitoes carrying viruses like West Nile
or eastern equine encephalitis could easily proliferate.